# CVE-2026-80991: net: ravb: serialize PTP clock teardown

CVE-2026-80991 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-80991, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-80991
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80991

## Description

In the Linux kernel, the following vulnerability has been resolved:  net: ravb: serialize PTP clock teardown  ravb_ptp_interrupt() can race with ravb_ptp_stop() and pass the clock to ptp_clock_event() while ptp_clock_unregister() is freeing it. This can lead to a use-after-free.  Use READ_ONCE() and WRITE_ONCE() for lockless access to the clock pointer. Atomically detach it with xchg() before disabling PTP interrupts, then synchronize all IRQs which can invoke ravb_ptp_interrupt() before unregistering the detached clock.  A handler which read the old pointer completes before the clock is unregistered, while later handlers read NULL and skip the event.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-80991](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80991.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-80991](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80991.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-80991](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80991.md) | Sep 23, 2026 |

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Data as of 2026-11-09T19:38:12Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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